Search

Background: Paper-based patient-reported outcome measures (PROMs) and patient education can assist in improving outcomes but is administratively burdensome. Mobile phone applications ('apps') can distribute extensive information and PROMs at relevant time points. This study aimed to assess the suitability of an app to guide postoperative management and record PROMs based on satisfaction and compliance., Methods: Thirty-four patients who were scheduled for a total hip/knee arthroplasty were enrolled into the study. Automatic notifications were sent by the app to complete PROMs at the appropriate time points. Patients were reminded via phone call if PROMs were not completed. An app satisfaction questionnaire was also completed, where a high score represented satisfaction with the app., Results: Patients remained satisfied with the app throughout the study with a mean score of 19.0 out of 25. 57% found the app to be helpful with completing surveys, with 63% preferring the app over paper handouts. Majority of the participants (68%) stated that they would use the app again. There was an overall mean compliance of 78% at all time points. Most patients (82%) required at least one phone call reminder, with 18% of patients completing their PROMs prompted by the app notification alone., Conclusions: A mobile phone app can be useful for both distributing patient education and collecting PROMs. PROMs collected using a mobile phone app still caused some administrative burden with many participants requiring multiple reminders to complete their questionnaires. While paper-forms will still be required for some patients, most found the app preferable to paper-form., (© 2024 The Authors.)

Background: Metal sensitivity is a possible cause for revision in elective lower-limb arthroplasty. This scoping review aims to identify and evaluate all existing and novel assessment methods for metal sensitivity in elective lower-limb arthroplasty., Methods: The Cochrane Central Register of Controlled Trials (CENTRAL), Ovid Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed, and Google Scholar databases were searched for studies published between January 1, 2000, and September 1, 2023. Studies evaluating one or more metal sensitivity assessment method preoperatively, perioperatively, or postoperatively were included. Studies were grouped based on the assessment methods reported and summarized based on the study design, outcome measure, results, and comments on the method's validity., Results: A total of 1220 results were screened, with 39 results (15 retrospective cohort studies, 11 prospective cohort studies, 6 case reports, 5 randomized controlled trials, and 2 case control studies) included, identifying 12 assessment methods. The most used one was patch testing, featuring in 17 studies (43.6%). Lymphocyte transformation assay/testing featured in 12 studies (30.8%). Plasma/serum concentration of metal ions featured in 6 studies (15.4%). Patient history and serum cytokine testing featured in 7 (17.9%) and 4 (10.3%) studies each. Generalized serum inflammatory markers featured in 3 studies (7.7%). The remaining 6 methods each featured in one or 2 studies. Evidence of the reliability of most metrics was limited., Conclusions: Several assessment methods were identified. However, evidence of any methods reliably predicting and diagnosing the occurrence of metal sensitivity was limited. There is a need for improved metrics of metal hypersensitivity., (© 2024 The Authors.)

Background: One of the most debated topics in modern total knee arthroplasty (TKA) is the impact of metal hypersensitivity (MH) as a potential cause of prosthesis failure. Implanting hypoallergenic prostheses to avoid potential problems in suspected cases of MH is one treatment option that can be used in such cases. However, their long-term clinical safety and efficacy are not well proven., Methods: All literature relevant to modern hypoallergenic implants were reviewed and summarized to provide a comprehensive synopsis. In addition, a detailed literature search was performed on PUBMED, MEDLINE, and Google Scholar to identify all the clinical studies reporting outcomes for hypoallergenic knee implants. Our search was confined to those studies published as full manuscripts in the English language from July 2018 to July 2023., Results: To minimize the risk of MH, new implant variants have been developed which are either under clinical evaluation or in routine clinical use. These include conventional metal implants with protective coatings (mono- or multilayer) and metal-free implants. However, there is insufficient clinical data to confirm the rationale and effectiveness of using these "hypoallergenic" TKA implants., Conclusions: Published studies and arthroplasty registry data analyses indicate no significant differences between hypoallergenic and standard TKAs with overall good survival rates. In the future, further high-quality studies are needed to better understand the complexity of this subject., (© 2024 The Authors.)

Background: A recent National Joint Registry report suggests a higher local complication risk for dual-mobility (DM) total hip arthroplasty (THA) compared to conventional articulation THA. This report may be subject to data heterogeneity with multiple confounders. Controlling for these factors by matching demographic characteristics may give different results. We aim to compare 2-year local complication rates between matched DM and conventional THAs in primary hip osteoarthritis., Methods: Data were collected for consecutive primary THAs undertaken via a posterior approach. The conventional articulation and DM cohorts were matched 3:1 for age, gender, American Society of Anesthesiology grade, body mass index, and operative time using a propensity score and nearest neighbor matching method. Outcome measures were 2-year local complication rates, reoperation rates, systemic complication rates, and mortality rates. Demographic and outcome data were compared, and cumulative survival rates (%) were assessed using Kaplan-Meier methodology with a 2-year local complication as the endpoint. Statistical significance was set at P < .05., Results: Four hundred twelve THAs were included: 309 conventional and 103 DM articulations. There were no statistically significant differences between DM and conventional articulation THAs for local complications (7 [6.8%] vs 23 [7.4%], P  = .820), reoperations (3 [2.9%] vs 4 [1.3%], P  = .374), systemic complications (3 [2.9%] vs 4 [1.3%], P  = .374), or 90-day mortality (1 [1%] vs 2 [0.6%], P  = 1.000). Kaplan-Meier survival analysis demonstrated similar 2-year survival rates for conventional THAs compared to DM THAs (93.3% [standard error, 0.014] vs 91.9% [standard error, 0.031], P  = .906)., Conclusions: This matched study shows that there is no difference in local complication rates between DM and conventional THA articulations., (© 2024 The Authors.)

Background: Several types of highly-crosslinked polyethylene with different manufacturing processes and mechanical properties are commercially available, including HIGHCROSS (Medacta). The aim of this registry study is to ascertain the long-term safety of the HIGHCROSS liners in total hip arthroplasty and compare the revision rates with its contemporaries using real-world data to establish their safety and generalizability when used by multiple surgeons., Methods: The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Swiss National Joint Registry (SIRIS) were selected for the large number of users of Medacta implants and the availability of long-term results. Three reports from SIRIS and 4 reports from AOANJRR were examined to establish the overall and Kaplan-Meier (KM) cumulative revision rate., Results: According to SIRIS, the HIGHCROSS liner was the most commonly used bearing surface with Medacta stems with overall revision rates for wear/osteolysis at 9.7 years of 0.04% and 0.03%, respectively, for AMIStem and Quadra. Based on AOANJRR, the KM cumulative revision rate for any reason of Medacta stems with HIGHCROSS liners was lower than that with ceramic liners at 3 years for MasterLoc and at 10 years for Quadra. The KM cumulative revision rate for any reasons of Medacta cementless cups with HIGHCROSS liners at 12 years was lower than the comparator made of all other implants and tribological couplings (1.6% vs 2.1%)., Conclusions: This real-world data proves that long-term HIGHCROSS survival rates are comparable to other modern bearing surfaces., (© 2023 The Authors.)

To enable long lasting osteochondral defect repairs which preserve the native function of synovial joint counter-face, it is essential to develop surfaces which are optimised to support healthy cartilage function by providing a hydrated, low friction and compliant sliding interface. PEEK surfaces were modified using a biocompatible 3-sulfopropyl methacrylate potassium salt (SPMK) through UV photo-polymerisation, resulting in a ∼350 nm thick hydrophilic coating rich in hydrophilic anionic sulfonic acid groups. Characterisation was done through Fourier Transformed Infrared Spectroscopy, Focused Ion Beam Scanning Electron Microscopy, and Water Contact Angle measurements. Using a Bruker UMT TriboLab, bovine cartilage sliding tests were conducted with real-time strain and shear force measurements, comparing untreated PEEK, SPMK functionalised PEEK (SPMK-g-PEEK), and Cobalt Chrome Molybdenum alloy. Tribological tests over 2.5 h at physiological loads (0.75 MPa) revealed that SPMK-g-PEEK maintains low friction (μ< 0.024) and minimises equilibrium strain, significantly reducing forces on the cartilage interface. Post-test analysis showed no notable damage to the cartilage interfacing against the SPMK functionalised surfaces. The application of a constitutive biphasic cartilage model to the experimental strain data reveals that SPMK surfaces increase the interfacial permeability of cartilage in sliding, facilitating fluid and strain recovery. Unlike previous demonstrations of sliding-induced tribological rehydration requiring specific hydrodynamic conditions, the SPMK-g-PEEK introduces a novel mode of tribological rehydration operating at low speeds and in a stationary contact area. SPMK-g-PEEK surfaces provide an enhanced cartilage counter-surface, which provides a highly hydrated and lubricious boundary layer along with supporting biphasic lubrication. Soft polymer surface functionalisation of orthopaedic implant surfaces are a promising approach for minimally invasive synovial joint repair with an enhanced bioinspired polyelectrolyte interface for sliding against cartilage. These hydrophilic surface coatings offer an enabling technology for the next generation of focal cartilage repair and hemiarthroplasty implant surfaces., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Robert Elkington reports financial support was provided by UK Research and Innovation., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Aim: This study aims to evaluate costs associated with periprosthetic femoral fracture (PFF) treatment at a UK tertiary referral centre., Methods: This study included 128 consecutive PFFs admitted from 02/04/2014-19/05/2020. Financial data were provided by Patient Level Information and Costing Systems. Primary outcomes were median cost and margin. Secondary outcomes were length of stay, blood transfusion, critical care, 30-day readmission, 2-year local complication, 2-year systemic complication, 2-year reoperation and 30-day mortality rates. Statistical comparisons were made between treatment type. Statistical significance was set at p<0.05., Results: Across the cohort, median cost was £15,644.00 (IQR £11,031.00-£22,255.00) and median loss was £3757.50 (£599.20-£8296.20). The highest costs were ward stay (£3994.00, IQR £1,765.00-£7,013.00), theatre utilisation (£2962.00, IQR £0.00-£4,286.00) and overheads (£1705.10, IQR £896.70-£2432.20). Cost (£17,455.00 [IQR, £13,194.00-£23,308.00] versus £7697.00 [IQR £3871.00-£10,847.00], p<0.001) and loss (£4890.00 [IQR £1308.00-£10,009.00] versus £1882.00 [IQR £313.00-£3851.00], p = 0.02) were greater in the operative versus the nonoperative group. There was no difference in cost (£17,634.00 [IQR £12,965.00-£22,958.00] versus £17,399.00 [IQR £13,394.00-£23,404.00], p = 0.98) or loss (£5374.00 [IQR £1950.00-£10,143.00] versus £3860.00 [IQR -£95.50-£7601.00], p = 0.21) between the open reduction and internal fixation (ORIF) and revision groups. More patients required blood transfusion in the operative versus the nonoperative group (17 [17.9%] versus 0 [0.0%], p = 0.009). There was no difference in any clinical outcome between the ORIF and revision groups (p>0.05)., Conclusion: PFF treatment costs are high with inadequate reimbursement from NHS tariff. Work is needed to address this disparity and reduce hospital costs. Cost should not be used to decide between ORIF and revision surgery., (Crown Copyright © 2022. Published by Elsevier Ltd. All rights reserved.)

The dynamic, complex interaction among the spine, pelvis, and hip is often underappreciated, yet understanding it is vital for both arthroplasty and spinal surgeons. There is an increasing incidence of degenerative hip and spinal pathologies as a result of the ageing population. Furthermore, hip pathology can cause spine pathology and vice versa through "hip-spine" and "spine-hip syndrome." Consequently, total hip arthroplasty (THA) and spinal fusion surgery, which both affect spinopelvic mobility, are also on the rise. Alteration in spinopelvic motion can affect the orientation of the acetabulum and, therefore, implant positioning in THA, leading to complications such as dislocation, impingement, aseptic loosening, and wear of components. This makes it imperative to assess spinopelvic motion and pelvic tilt prior to patients undergoing THA. In this paper, we explore how the surgeon should proceed to reduce risk of component malalignment, as well as the role of navigation systems in acetabular cup positioning., (© 2022 The Authors.)

Background: There is limited evidence available on return to driving for patients undergoing knee arthroplasty (KA). Primarily, surgeons have used brake reaction time as a surrogate measure of safe return to driving. The purpose of this study was to review existing literature and provide guidance on the recovery of braking performance following knee arthroplasty., Methods: A literature search was performed for prospective studies on driving after KA. Two reviewers screened citations for inclusion, assessed methodological quality, and extracted data. Values for total brake reaction-time (TBRT), movement-time (MT), reaction-time (RT), and braking-force (BF) were included for meta-analysis., Results: Twelve studies with 368 subjects were identified. TBRT, RT, MT, and BF relative to preoperative baseline were assessed. Meta-analysis of TBRT showed a significant improvement from preoperative baseline at 3 months & 1 year (p = 0.003 & p = 0.0001). MT showed a significant increase at 2 and 4 weeks (p = 0.00001 & p = 0.03) before returning to no being significantly different at 6 weeks and beyond. In contrast RTs were noted to improve significantly 2 weeks (p = 0.006), 4 weeks (p = 0.03), and 1 year (p = 0.0002)., Conclusion: Meta-analysis showed no significant difference in TBRT up until 3 months. RT increased significantly post-operatively suggesting it is not a reliable indicator. MT in contrast was significantly decreased post KA and may represent a more reliable measure of braking performance post KA. Surgeons should consider these recommendations and other patient factors that determine fitness to drive prior to advising their patients on a safe to return to driving., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Professor Pandit is a National Institute for Health Research (NIHR) Senior Investigator. Mr van Duren is a BRC-NIHR Academic Clinical Lecturer. The views expressed in this article are those of the author(s) and not necessarily those of the BRC, NIHR, or the Department of Health and Social Care., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: To assess the quality and duration of trauma and orthopedics (T&O) training in medical schools in United Kingdom (UK), and to evaluate final-year students' self-perceived level of competence in essential T&O skills., Design: This was a survey-based study of final-year medical students that attended 1-day undergraduate T&O courses held between Feb'17 and Feb'19. Outcome measures were duration and perceived quality of undergraduate T&O placements, students' self-rated competence in essential T&O skills, and impact of teaching methods on their subjective future competence., Setting: Four courses held at education centers in 3 different locations in UK (London, Nottingham, and Leeds) PARTICIPANTS: All 414 course attendees from 13 UK medical schools completed the questionnaire., Results: 19.3% of students had not experienced a placement in T&O. Mean duration of T&O placements was 2.5 weeks. 37.4% described their training as "poor". Majority of students attended 1-5 sessions of: lectures (50.5%), small group teaching (58.7%), trauma meetings (58.7%), clinics (65.7%), and theatres (72.5%). Lowest competency scores were reported in management of T&O emergencies, fracture management, and interpretation of T&O radiographs. Self-rated competence in essential T&O skills was significantly higher in students with previous experience of a T&O placement (p < 0.05). There was a strongly positive correlation between small group teaching attendance and perceived competence in management of T&O patients in different clinical settings (p < 0.001)., Conclusions: Medical schools in UK are currently failing to adequately train medical graduates to manage T&O patients, with students reporting low competency scores in all basic T&O skills. To mitigate the current situation, a minimum duration of a T&O placement for all students must be implemented nationally. Educational boards and medical schools must work in collaboration to improve the delivery of undergraduate T&O curriculum, the structure of the clinical T&O placement, and efficacy of the commonly encountered learning environments., (Copyright © 2020 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.)

As life expectancy and activity levels of patients increase so does the demand on total knee replacements (TKRs). Abnormal mechanics and wear of TKRs can lead to implant loosening and revision. Component alignment after surgery varies due to the presurgical alignment, the accuracy of the surgical instrumentation and due to patient factors, such as the soft tissue balance. This study experimentally investigated the effect of variation in component alignment and the soft tissue conditions on the kinematics and wear of a fixed bearing TKR. DePuy Sigma fixed bearing TKRs with moderately cross-linked UHMWPE were used. Different alignment conditions were simulated in the coronal, sagittal and transverse planes in an ISO force-controlled simulation system. Three different soft tissue conditions were simulated using virtual springs to represent a stiff knee, a preserved PCL and a resected PCL. Four different alignment conditions were studied; ideal alignment, 4° tibial and femoral varus joint line, 14° rotational mismatch and 10° posterior tibial slope. The varus joint line alignment resulted in similar kinematics and lower wear rate compared to ideal alignment. The rotational mismatch alignment resulted in significantly higher tibial rotation and abduction-adduction as well as a significantly higher wear rate than ideal alignment. The posterior tibial slope alignment resulted in significantly higher wear than the ideal alignment and dislocated under the lower tension soft tissue conditions. Component alignment and the soft tissue conditions had a significant effect on the kinematics and wear of the TKR investigated in this study. The surgical alignment of the TKR is an important factor in the clinical outcome of the joint as factors such as increased tibial rotation can lead to anterior knee pain and instability and increased wear can lead to aseptic loosening and early failure resulting in revision., (Copyright © 2019. Published by Elsevier Ltd.)

Background: The management of the infrapatellar fat pad (IPFP) during total knee arthroplasty (TKA) is the subject of ongoing debate. In part 1 of this two-part series, we present an overview of current practice regarding the management of the IPFP in elective TKA among surgeons in the UK., Methods: A web-based survey was offered to 269 delegates of the BASK 2017 annual conference., Results: The survey showed a large variation in practice. Of the 173 responders, 86.7% were consultants; 62.4% partially resected the IPFP; 23.1% totally resected the IPFP, and 9.8% preserved it. Forty percent felt that resection made a difference. Only 23% stated that they were aware of guidelines/evidence., Conclusion: There is wide variation in practice with regard to the IPFP in TKA. The available literature with regard to resection or preservation of the IPFP is not conclusive., Implications: There are no definitive guidelines available for the management of the IPFP in TKA resulting in a wide variation in practice amongst surgeons., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: The management of the infrapatellar fat pad (IPFP) during total knee arthroplasty (TKA) is the subject of ongoing debate. In part 2 of this two part series the authors aimed to investigate if resection of the IPFP affects clinical outcomes., Methods: A systematic search of CENTRAL Cochrane library, Medline, Embase and Web-of-science databases for the past 10 years was performed. Studies of patients undergoing primary TKA comparing outcomes between IPFP resection and preservation were included. The meta-analysis was performed with Review Manager 5.3., Results: Seven studies, involving 2815 patients (3312 knees) were included in the systematic review, of which two were RCTs. Outcome measures included patellar tendon length (PTL), post-operative pain, Knee Society Scores (KSS) and Functional Scores. Meta-analysis identified a trend toward shortening of the patellar tendon with IPFP resection. Resection correlated with a lower incidence of post-operative pain at one to two months, however at three to six months pain scores were higher in this group. No statistical difference was found in KSS and Functional Scores., Conclusion: There is wide variation in practice with regard to the IPFP in TKA. The available literature with regard to resection or preservation of the IPFP is not conclusive., Implications: There is no clear consensus in the literature on the resection or preservation of the IPFP indicating a clear need for high quality studies in the future to provide meaningful answers., (Copyright © 2019. Published by Elsevier B.V.)

Background: Anti-PDL-1 immunotherapy for Hepatocellular Carcinoma (HCC) demonstrated a mixed response. Polycomb Repressor Complex 2(PRC2) contributes to the initiation and progression of HCC by suppressing tumor antigens and inhibiting an immune response. Two components of epigenetic modulation are Enhancer of Zeste Homolog 2 (EZH2, the catalytic component of PRC2) and DNA Methyltransferase 1 (DNMT1). We aim to investigate the potential role of epigenetic therapy targeting EZH2 and DNMT1 as a novel strategy to modulate immunotherapy response in HCC., Methods: HepG2, Hep3B, and Hepa1-6 HCC cell lines were treated with EZH2 inhibitor (DZNep) and DNMT1 inhibitor (5-Azacytidine) with and without anti-PDL-1. Quantitative RT-PCR and immunohistochemistry were performed to evaluate the expression of tumor suppressors, tumor antigens, and Th1 chemokines. In-vivo C57/LJ immunocompetent mice model with subcutaneous tumor inoculation was performed with intraperitoneal drug injections., Results: There was a significant upregulation of Th1 chemokines in HepG2 (CXCL9 5.5 ± 0.2 relative fold change; CXCL10 1.44 × 103 ± 37 relative fold change) and Hep3B (CXCL 9 6.85 × 103 ± 1.3 × 103 relative fold change; CXCL 10 2.15 × 103 ± 3.1 × 102 relative fold change). Additionally, there was a significant induction of cancer testis antigens NY-ESO-1 (3.6-3.7 ± 0.3 relative fold change) and LAGE (8.3-11.7 ± 1.9 relative fold change). In vivo model demonstrated statistically significant tumor regression in the combination treatment group (0.02 g ± 0.02) compared to epigenetic therapy (0.63 g ± 0.61) or immunotherapy alone (0.15 g ± 0.21) with untreated control (2.4 g ± 0.71). There was significantly increased trafficking of cytotoxic T- lymphocytes and associated apoptosis for the combination treatment group compared to epigenetic or immunotherapy alone., Conclusions: This study demonstrates that epigenetic modulation could be a novel potential strategy to augment immunotherapy for HCC by stimulating T cell trafficking into tumor microenvironment via activation of transcriptionally repressed chemokine genes responsible for T-cell trafficking, inducing previously silent neoantigens for immune targets, and allowing tumor regression as a result. A clinical trial of this feasible combination therapy of these clinically available agents is warranted., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Cementless fixation is an alternative to cemented unicompartmental knee replacement (UKR), with several advantages over cementation. This study reports the ten-year survival and seven-year clinical outcome of cementless Oxford unicompartmental knee replacement (OUKR)., Methods: This prospective study describes the clinical outcome and survival of the first 1000 consecutive cementless medial OUKRs implanted at two centres for recommended indications., Results: The 10-year survival was 97% (CI 95%: 92-100%), with 25 knees being revised. The commonest reason for revision was progression of arthritis laterally, which occurred in nine knees, followed by primary dislocation of the bearing, which occurred in six knees. There were two dislocations secondary to trauma and a ruptured ACL, and two tibial plateau fractures. Although there were no definite cases of aseptic loosening, two early revisions were related to tibial fixation: one for pain and a radiolucent line and one for incomplete seating of the component with a radiolucent line. There were four revisions for pain, but the cause of the pain was uncertain: in one there was tibial overhang and in two there was patellofemoral degeneration, which possibly contributed to the pain. There were no deep infections. The mean OKS improved from 23 (SD 8) to 42 (SD 7) at a mean follow-up of 7.0 years (p < 0.001). There was no significant difference in survival or clinical outcome between the designer and independent centre., Conclusions: The cementless OUKR is a safe and reproducible procedure with excellent 10-year survival and clinical results in the hands of both designer and independent surgeons., (Copyright © 2018. Published by Elsevier B.V.)

As life expectancy and activity levels of patients increase so does the demand on total knee replacements (TKRs). Abnormal mechanics and wear of TKRs can lead to implant loosening and early failure. Polyethylene inserts of varying design and conformity have been introduced in the past decade to improve stability and patient's confidence in the replaced knee, particularly in cases where soft tissue support around the knee is sub optimal. This study experimentally investigated the effect of variation in the soft tissues on the kinematics and wear of a TKR on three different tibial insert designs. DePuy Sigma fixed bearing TKRs with moderately cross-linked UHMWPE and the ISO force control inputs were used. Different soft tissue constraints were simulated using virtual springs in an ISO force controlled simulation system. The spring gaps and stiffness' were varied and their effect on the output kinematics and wear rates assessed. The lower conformity inserts resulted in significantly higher displacements and more variation between the stations on the simulator. They were also more sensitive to changes in the soft tissue constraints than the high conformity insert. The wear rate for the high tension springs was significantly lower than for the lower tension springs tested. Tibial insert geometry and soft tissue constraints significantly affected kinematics and wear in these experimental simulations. Soft tissue constraints and the variability in patients are important considerations in the stratified design of TKRs and approach to patient selection., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Many different measures have been used to describe knee kinematics. This study investigated the changes of two measures, the patellar tendon angle and the patellar flexion angle, in response to variations in the geometry of the knee due to surgical technique or implant design., Methods: A mathematical model was developed to calculate the equilibrium position of the extensor mechanism for a particular tibiofemoral position. Calculating the position of the extensor mechanism allowed for the determination of the patellar tendon angle and patellar flexion angle relationships to the knee flexion angle. The model was used to investigate the effect of anterior-posterior position of the femur, change in joint line, patellar thickness (overstuffing, understuffing), and patellar tendon length; these parameters were varied to determine the effect on the patellar tendon angle/knee flexion angle and patellar flexion angle/knee flexion angle relationships., Results: The patellar tendon angle was a good indicator of anterior-posterior femoral position and change in patellar thickness, and the patellar flexion angle a good indicator of change in joint line, and patellar tendon length., Conclusions: The patellar tendon angle/knee flexion angle relationship was found to be an effective means of identifying abnormal kinematics post-knee arthroplasty. However, the use of both the patellar tendon angle and patellar flexion angle together provided a more informative overview of the sagittal plane kinematics of the knee., (Copyright © 2018. Published by Elsevier B.V.)

Background: Trauma courses have been shown to improve clinical knowledge and patient outcomes. However, little is known about the individual drivers of change in practice amongst course participants in their home clinic environment., Methods: Front-line healthcare workers participated in a two-day Primary Trauma Care (PTC) course. Immediately after the course participants completed an evaluation survey on intended change in the management of trauma patients. Six months after the course, participants completed a survey on actual changes that had occurred., Results: A total of 451 participants were sampled, with 321 responding at 6 months, from 40 courses across East, Central and Southern Africa. The most commonly reported intended change was the adoption of an ABCDE/systematic approach (53%). Six months after the course, 92.7% of respondents reported that they had made changes in their management, with adoption of an ABCDE/systematic approach (50.0%) remaining most common. 77% of participants reported an improvement in departmental trauma management, 26% reported an increase in staffing, 29% an increase in equipment and 68% of participants had gone on to train other healthcare workers in PTC., Conclusion: The findings suggest that PTC courses not only improve individual management of trauma patients but also but is also associated with beneficial effects for participants' host institutions with regards to staffing, equipment and training., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: We conducted an assessment of orthopaedic surgical capacity in the following countries in East, Central, and Southern Africa: Burundi, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe., Methods: We adapted the WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care with questions specific to trauma and orthopaedic care. In May 2013-May 2014, surgeons from the College of Surgeons of East, Central and Southern Africa (COSECSA) based at district (secondary) and referral (tertiary) hospitals in the region completed a web-based survey. COSECSA members contacted other eligible hospitals in their country to collect further data., Findings: Data were collected from 267 out of 992 (27%) hospitals, including 185 district hospitals and 82 referral hospitals. Formal accident and emergency departments were present in 31% of hospitals. Most hospitals had no general or orthopaedic surgeons or medically-qualified anaesthetists on staff. Functioning mobile C-arm X-ray machines were available in only 4% of district and 27% of referral hospitals; CT scanning was available in only 3% and 26%, respectively. Closed fracture treatment was offered in 72% of the hospitals. While 20% of district and 49% of referral hospitals reported adequate instruments for the surgical treatment of fractures, only 4% and 10%, respectively, had a sustainable supply of fracture implants. Elective orthopaedic surgery was offered in 29% and Ponseti treatment of clubfoot was available at 42% of the hospitals., Interpretation: The current capacity of hospitals in sub-Saharan Africa to manage traumatic injuries and orthopaedic conditions is significantly limited. In light of the growing burden of trauma and musculoskeletal impairment within this region, concerted efforts should be made to improve hospital capacity with equipment, trained personnel, and specialist clinical services., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Injuries cause five million deaths and 279 Disability Adjusted Life Years (DALYS) each year worldwide. The COSECSA Oxford Orthopaedic Link (COOL) is a multi-country partnership programme that has delivered training in trauma management to nine sub-Saharan countries across a wide-cadre of health-workers using a model of "primary" courses delivered by UK instructors, followed by "cascading" courses led by local faculty. This study examines the impact on knowledge and clinical confidence among health-workers, and compares the performance of "cascading" and "primary" courses delivered in low-resource settings., Methods: Data was collated from 1030 candidates (119 Clinical Officers, 540 Doctors, 260 Nurses and 111 Medical Students) trained over 28 courses (9 "primary" and 19 "cascading" courses) in nine sub-Saharan countries between 2012 and 2013. Knowledge and clinical confidence of candidates were assessed using pre- and post-course MCQs and confidence matrix rating of clinical scenarios. Changes were measured in relation to co-variants of gender, job roles and primary versus cascading courses. Multivariate regression modelling and cost analysis was performed to examine the impact of primary versus cascading courses on candidates' performance., Findings: There was a significant improvement in knowledge (58% to 77%, p<0.05) and clinical confidence (68% to 90%, p<0.05) post-course. "Non-doctors" demonstrated a greater improvement in knowledge (22%) and confidence (24%) following the course (p<0.05). The degree of improvement of MCQ scores differed significantly, with the cascading courses (21%) outperforming primary courses (15%) (p<0.002). This is further supported by multivariate regression modelling where cascading courses are a strong predictor for improvement in MCQ scores (Coef=4.83, p<0.05)., Interpretation: Trauma management training of health-workers plays a pivotal role in tackling the ever-growing trauma burden in Africa. Our study suggests cascading PTC courses may be an effective model in delivering trauma training in low-resource settings, however further studies are required to determine its efficacy in improving clinical competence and retention of knowledge and skills in the long term., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: High levels of activity are considered to be a contraindication to unicompartmental knee replacement (UKR) and are not recommended after UKR. To determine if these recommendations should apply to the mobile-bearing Oxford UKR, this study assessed the effect of post-operative activity level on the outcome of this device., Methods: The outcome of the first 1000 Phase 3 cemented Oxford UKRs implanted between 1998 and 2010 was assessed using survival analysis, the Oxford Knee Score (OKS) and the American Knee Society Objective (KSS-O) and Functional (KSS-F) Scores. Patients were grouped according to the maximum post-operative Tegner Activity Score., Results: The mean follow-up was 6.1 years (range 1 to 14). Overall, increasing activity was associated with superior survival (p=0.025). In the high activity group, with Tegner≥5 (n=115) 2.6% were revised and the 12-year survival was 97.3% (confidence interval (CI): 92.0% to 99.1%). In the low activity group, with Tegner≤4, (n=885) 4.3% were revised and the 12-year survival was 94.0% (CI: 91.4 to 95.8). The difference between the two groups was not significant (p=0.44). Although the final OKS and KSS-F were significantly better in the high activity group compared to the low activity group (OKS 45v40, KSS-F 95v78), there was no difference in the change in OKS or KSS-O., Conclusions: High activity does not compromise the outcome of the Oxford UKR and may improve it. Activity should not be restricted nor considered to be a contraindication., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Surfactant proteins SP-A and SP-D are pattern recognition innate immune molecules that belong to the C-type lectin family. In lungs, they play an important role in the clearance of pathogens and control of inflammation. SP-A and SP-D are also expressed in the female reproductive tract where they play an important role in pregnancy and parturition. However, the role of SP-A and SP-D expressed at the feto-maternal interface (decidua) remains unclear. Here, we have examined the expression of SP-A and SP-D in the murine decidua at 17.5 (pre-parturition) and 19.5dpc (near parturition) and their effect on lipopolysaccharide (LPS)-treated decidual macrophages. SP-A and SP-D were localized to stromal cells in the murine decidua at 17.5 and 19.5dpc in addition to cells lining the maternal spiral artery. Purified pre-parturition decidual cells were challenged with LPS with and without SP-A or SP-D, and expression of F4/80 and TNF-α were measured by flow cytometry. On their own, SP-A or SP-D did not affect the percentage of F4/80 positive cells while they suppressed the percentage of TNF-α positive cells. However, simultaneous addition of SP-A or SP-D, together with LPS, reduced TNF-α secreting F4/80 positive cells. It is likely that exogenous administration of SP-A and SP-D in decidua can potentially control infection and inflammation mediators during spontaneous term labor and infection-induced preterm labor. Thus, the presence of SP-A and SP-D in the murine decidua is likely to play a protective role against intrauterine infection during pregnancy., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Surfactant protein D (SP-D) is an integral molecule of the innate immunity secreted by epithelial cells lining the mucosal surfaces. The C-type lectin domain of SP-D performs pattern recognition functions while it binds to putative receptors on immune cells to modify cellular functions. Activation of immune cells and increased serum SP-D is observed in a range of patho-physiological conditions including infections. We speculated if SP-D can modulate systemic immune response via direct interaction with activated PBMCs. In this study, we examined interaction of a recombinant fragment of human SP-D (rhSP-D) on PHA-activated PBMCs. We report a significant downregulation of activation receptors such as TLR2, TLR4, CD11c and CD69 upon rhSP-D treatment. rhSP-D inhibited production of Th1 (TNF-α and IFN-γ) and Th17 (IL-17A) cytokines along with IL-6. Interestingly, levels of IL-2, Th2 (IL-4) and regulatory (IL-10 and TGF-β) cytokines remained unaltered. Analysis of co-stimulatory CD28 and co-inhibitory CTLA4 receptors along with their ligands CD80 and CD86 revealed a selective up-regulation of CTLA4 in the lymphocyte subset. rhSP-D induced apoptosis in the activated but not in non-activated lymphocytes. Blockade of CTLA4 inhibited rhSP-D mediated apoptosis of activated lymphocytes, confirming involvement of CTLA4. We conclude that SP-D restores immune homeostasis. It regulates expression of immunomodulatory receptors and cytokines, which is followed by induction of apoptosis in activated lymphocytes. These findings suggest a critical role of SP-D in immune surveillance against activated immune cells., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Introduction: More than five million deaths occur each year from injury with the vast majority occurring in low and middle-income countries (LMICs). Africa bears the highest road traffic related mortality rates in the world. Despite this, formal training in trauma management is not widely adopted in these countries. We report our results of 10 consecutive Primary Trauma Care (PTC) courses delivered in seven East and Central African countries, as part of the COSECSA Oxford Orthopaedic Link (COOL) initiative., Methods: Candidate's knowledge and clinical confidence in trauma management were assessed using a multiple-choice questionnaire and a confidence matrix rating of eight clinical scenarios. We performed descriptive statistical analysis on knowledge and clinical confidence scores of candidates before and after the course. We sub-analysed these scores, examining specifically the difference that exist between gender, job-roles and instructors versus non-instructors., Results: We have trained 345 new PTC providers and 99 new PTC instructors over the 10 courses. Data sets were complete for 322 candidates. Just under a third of candidates were women (n=94). Over two-thirds of candidates (n=240) were doctors, while the remainder comprised of nurses, medical students and clinical officers. Overall, the median pre-course MCQ score was 70% which increased to 87% post course (p<0.05). Men achieved a higher MCQ score both pre- and post-course compared to women (p<0.05); however there was no significant difference in the degree of improvement of MCQ scores between gender. Instructors outperform non-instructors (p<0.05), and similarly doctors outperform non-doctors on final MCQ scores (post-course). However, it was the non-doctors who showed a statistically significant improvement in scores before and after the course (20% non-doctors vs 16% doctors, p<0.05). Candidate's clinical confidence also demonstrated significant improvement following the course (p<0.05)., Conclusion: Our work demonstrates that COOL-funded PTC courses in the COSECSA region delivered to front-line health staff have helped improve their knowledge and confidence in trauma management, irrespective of their job-roles and gender. Further follow-up is needed to establish the long-term impact of PTC courses in this region., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Trauma and road traffic accidents are predicted to increase significantly in the next decade in low-income and middle-income countries. The College of Surgeons of East, Central, and Southern Africa (COSECSA) covers Ethiopia, Kenya, Tanzania, Uganda, Rwanda, Burundi, Mozambique, Malawi, Zimbabwe, and Zambia. Ministry of Health websites for these ten countries show that 992 hospitals are covering an estimated 318 million people., Methods: The WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care was used with added questions relevant to trauma and orthopaedic care. A web-based survey platform was used and hospitals were contacted via COSECSA representatives. Consent to share data was requested, anonymised for country and hospital., Findings: 267 (27%) of 992 hospitals completed the survey. 185 were district level hospitals and 82 were referral or tertiary level hospitals. Formal accident and emergency departments were present in only 29% of district hospitals (95% CI 22·5-35·5) and 35% (24·7-45·3) of referral or tertiary level hospitals. The mean number (SD) of surgeons was 1·4 (3·0) in district hospitals and 2·6 (4·6) in referral or tertiary level hospitals. The mean number (SD) of orthopaedic surgeons was 0·3 (0·9) in district hospitals and 0·5 (0·9) in referral or tertiary level hospitals. Medically qualified anaesthetists were available in 16% (95% CI 10·7-21·3) of district hospitals and 20% (11·4-28·6) of referral or tertiary level hospitals. C arm radiography was available in 3% (95% CI 0·5-5·5) of district hospitals and 32% (21·9-42·1) of referral or tertiary level hospitals. CT scanning was available in 6% (95% CI 2·6- 9·4) of district hospitals and 21% (12·2-29·8) of referral or tertiary level hospitals. Closed fracture treatment was offered in 75% (95% CI 68·8- 81·2) of district hospitals and 82% (73·7-90·3) of referral or tertiary level hospitals. 37% (95% CI 30·1-43·9) of district hospitals and 40% (29·4-50·6) of referral or tertiary level hospitals had adequate instruments for the surgical treatment of fractures, but only 7% (3·4-10·6) of district hospitals and 8% (2·1-13·9) of referral or tertiary level hospitals had a sustainable supply of fracture implants. Elective orthopaedic surgery took place in 30% (95% 23·4- 36·6) of district hospitals and 34% (23·8-44·2) of referral or tertiary level hospitals. Ponseti treatment of clubfoot was available at 46% (95% 38·8-53·2) of district hospitals and 44% (33·3-54·7) of referral or tertiary level hospitals., Interpretation: This study has limitations in that only 27% of eligible hospitals completed the survey, and it is certainly possible that there could be bias in that the less well resourced institutions could also be less likely to cooperate with data collection. Thus, it is possible that the figures we present overestimate the resources available in the region as a whole. However, despite the limitations in data quality, it is clear that current capacity to treat trauma and orthopaedic conditions is very limited, with particular areas of concern being manpower, training, facilities, and equipment. COSECSA will use these data as a baseline for further surveys and to develop a strategy to improve trauma and orthopaedic care in the region., Funding: UK Department for International Development (DFID)., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Africa has one of the highest road-traffic mortality rates in the world. Nurses and clinical officers play a pivotal part in trauma care as a result of substantial shortage of doctors. The COOL (COSECSA-Oxford-Orthopaedic-Link) programme has delivered primary trauma care (PTC) training in nine sub-Saharan African countries across a wide cadre of health-workers (540 doctors, 260 nurses, 119 clinical officers, and 111 medical students). This prospective study investigates the effect of 28 consecutive PTCs and the training challenges that exist between different cadres and health institutions., Methods: The course trains delegates in key trauma concepts: primary survey, airway management, chest injuries, major haemorrhage, and paediatric trauma. Candidates' knowledge of these concepts was assessed before and after the course with a validated 30 Single-Best-Answer multiple choice questionnaire. Assessment scores were analysed by cadre, urban (383 candidates) or rural institutions (647 candidates), and sex (657 men, 373 women). A concept was categorised as being poorly understood when half the candidates achieved less than 50% of the correct answers. Descriptive statistics and MANOVA analysis were used, with an alpha level set at 0·05., Findings: 1030 PTC providers were trained between Dec 5, 2012, and Dec 19, 2013. There was significant increase in multiple choice questionnaire (58% to 77%, p<0·05) and clinical confidence (68% to 90%, p<0·05) scores among delegates post course, with independent covariants of institution location and cadre significantly affecting post-course scores. Doctors achieved satisfactory scores on all key concepts (67% to 84%, p<0·05). Clinical officers (all concepts 53% to 76%, p<0·05) particularly struggled with paediatric trauma (94 candidates <50%, mean 24·23 [95% CI 19-30]). Nurses (all concepts 42% to 64%, p<0·05) had difficulty with chest injuries (203 pre-course to 153 post-course candidates <50%, mean 49% [95% CI 45-52]) and paediatric trauma (212 pre-course to 161 post-course candidates ≤50%, post course mean 46% [95% CI 43-53]). Medical students achieved satisfactory scores in all concepts (overall 53% to 74%, p<0·05). Health-workers based in urban hospitals (82%) outperformed those in rural hospitals (72%) (p=0·001) and sex had no significant effect on performance (p=0·07)., Interpretation: Our study shows that PTC courses led to improvement in trauma management knowledge and clinical confidence among a wide cadre of health-workers. However, these are new concepts for many front-line health-workers, and regular refresher training will be required. There is also a difference in understanding of key trauma concepts among the different cadres. Future training in this region should address areas of weakness unique to each cadre, particularly paediatric trauma care., Funding: Health Partnership Scheme through the UK Department for International Development (DFID)., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Injury accounts for 267 000 deaths annually in the nine College of Surgeons of East, Central, and Southern Africa (COSECSA-ASESA) countries, and the introduction of a sustainable standardised trauma training programme across all cadres is essential. We have delivered a primary trauma care (PTC) programme that encompasses both a "provider" and "training the trainers" course using a "cascading training model" across nine COSECSA countries. The first "primary course" in each country is delivered by a team of UK instructors, followed by "cascading courses" to more rural regions led by newly qualified local instructors, with mentorship provided by UK instructors. This study examines the programme's effectiveness in terms of knowledge, clinical confidence, and cost-effectiveness., Methods: We collected pre-training and post-training data from 1030 candidates (119 clinical officers, 540 doctors, 260 nurses, and 111 medical students) trained over 28 courses (nine primary and 19 cascading courses) between Dec 5, 2012, and Dec 19, 2013. Knowledge was assessed with a validated PTC multiple choice questionnaire and clinical confidence ratings of eight trauma scenarios, measured against covariants of sex, age, clinical experience, job roles, country, and health institution's workload., Findings: Post-training, a significant improvement was noted across all cadres in knowledge (19% [95% CI 18·0-19·5]; p<0·05) and clinical confidence (22% [20·3-22·3]; p<0·05). Non-doctors showed a greater improvement in knowledge (22% vs 16%; p<0·05) and confidence (24% vs 20%; p<0·05) than doctors. Candidates attending cascading courses also showed larger improvements in knowledge (21% vs 15%; p<0·002) and clinical confidence (23% vs 19%; p<0·002) than their primary course counterparts. Multivariate regression analysis showed that attending cascading courses (Coef=4·83, p<0·05), being a nurse (Coef=3·89, p=0·007) or a clinical officer (Coef=4·11, p=0·015), and attending a course in Kenya (Coef=9·55, p<0·002) or Tanzania (Coef=9·40, p<0·002) were strong predictors to improvement in multiple choice questionnaire performance. However, improvement in clinical confidence was affected by the job-role of the clinical officer (Coef=6·49, p=0·002) and attending a course in Kenya (Coef=16·12, p<0·02) or Tanzania (Coef=7·01, p<0·05). Cascading courses were on average £2000 less expensive than primary care courses., Interpretation: To the best of our knowledge, this is the largest series in the literature on multicountry trauma management training in sub-Saharan Africa. Our study supports the concept of cascading courses as an educationally and cost-effective method in delivering vital trauma training in low-resource settings led by local clinicians., Funding: Health Partnership Scheme through the UK Department for International Development (DFID)., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: The rate of bearing dislocation with the domed lateral Oxford Unicompartmental Knee Replacement (OUKR) in different series varies from 1% to 6% suggesting that dislocation is influenced by surgical technique. The aim of this study was to identify surgical factors associated with dislocation., Methods: Aligned post-operative antero-posterior knee radiographs of seven knees that had dislocated and 87 control knees were compared. Component alignment and position and the alignment of the knee were assessed. All bearing dislocations occurred medially over the tibial wall., Results: Knees that dislocated tended to be overcorrected: Compared with those that did not dislocate, they were in 2° less valgus (p=0.019) and the tibial components were positioned 2 mm more proximal (p<0.01). Although the relative position of the centre of the femoral component and the tibial component was the same (p=0.8), in the dislocating group the gap between the edge of the femoral component and the top of the wall in flexion was 3mm greater (p=0.019) suggesting that the components were internally rotated., Conclusions: To minimise the risk of dislocation it is recommended that the knee should not be overstuffed. This is best achieved by selecting the bearing thickness that just tightens the ligaments in full extension, and re-cutting the tibia if necessary. In addition to minimise the gap between the femoral and tibial components through which the bearing dislocates, the femoral component should be implanted in neutral rotation and should not be internally rotated., Level of Evidence: Level IV., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Few injury surveillance systems collect data in sub-Saharan Africa. This medical record review of four rural hospitals provides baseline data on the burden of trauma in Malawi., Methods: We reviewed all outpatient, inpatient, and mortuary records for one full year at four of the 28 district hospitals in Malawi: Dedza in central Malawi, Mangochi in the east, Nkhata Bay in the north, and Thyolo in the south. We used descriptive and comparative statistics to examine characteristics of patients and the data file., Results: During 2012, 18,735 trauma patients were treated at the four district hospitals. Trauma cases accounted for 3.5% of the 541,170 patient visits. In total, 60.8% of trauma patients were male; 39.1% were 0–14 years old and 50.4% were 15–49 years old. The logbooks were missing information about the primary type of injury for 44.9% of patients and about injury cause for 82.7%. Of the recorded trauma diagnoses, the most common injuries were soft tissue injuries, fractures, and sprains. The most commonly reported causes of injuries were animal bites (mostly dog bites), road traffic injuries, assaults, burns, and falls., Conclusions: The development and implementation of improved methods for acquiring more complete, accurate, and useful trauma data in Malawi and other low-income countries requires addressing difficulties that might result in missing data. Increased injury surveillance is critical for improving trauma care and meeting the emerging global demand for burden of disease data.

Background: Total knee replacement (TKR) or unicompartmental knee replacement (UKR) are options for end-stage osteoarthritis. However, comparisons between the two procedures are confounded by differences in baseline characteristics of patients undergoing either procedure and by insufficient reporting of endpoints other than revision. We aimed to compare adverse outcomes for each procedure in matched patients., Methods: With propensity score techniques, we compared matched patients undergoing TKR and UKR in the National Joint Registry for England and Wales. The National Joint Registry started collecting data in April 1, 2003, and is continuing. The last operation date in the extract of data used in our study was Aug 28, 2012. We linked data for multiple potential confounders from the National Health Service Hospital Episode Statistics database. We used regression models to compare outcomes including rates of revision, revision/reoperation, complications, readmission, mortality, and length of stay., Findings: 25,334 UKRs were matched to 75,996 TKRs on the basis of propensity score. UKRs had worse implant survival both for revision (subhazard ratio [SHR] 2·12, 95% CI 1·99–2·26) and for revision/reoperation (1·38, 1·31–1·44) than TKRs at 8 years. Mortality was significantly higher for TKR at all timepoints than for UKR (30 day: hazard ratio 0·23, 95% CI 0·11–0·50; 8 year: 0·85, 0·79–0·92). Length of stay, complications (including thromboembolism, myocardial infarction, and stroke), and rate of readmission were all higher for TKR than for UKR., Interpretation: In decisions about which procedure to offer, the higher revision/reoperation rate of UKR than of TKR should be balanced against a lower occurrence of complications, readmission, and mortality, together with known benefits for UKR in terms of postoperative function. If 100 patients receiving TKR received UKR instead, the result would be around one fewer death and three more reoperations in the first 4 years after surgery., Funding: Royal College of Surgeons of England and Arthritis Research UK.

Infection in external fixator pins is known to be a significant problem, with incidences between 3% and 80% reported in the literature. An infection occurs when planktonic bacteria adhere to external fixator pins and subsequently produce a biofilm which protects the bacteria from host defences. The most commonly implicated organisms are Staphylococcus aureus and Staphylococcus epidermidis. Once an infection occurs, treatment is difficult. Systemic antibiotics have limited benefits and considerable side-effects. The only definitive management is removal of the pin. This review will consider the current and potential future strategies for reducing pin site infection. Techniques to prevent infection must prevent bacterial adhesion, allow good osteointegration and have a low toxicity. Current areas of interest reviewed are titanium-copper alloys, nanosilver coatings, nitric oxide coatings, chitosan coatings, chlorhexidine and iodine, hydroxyapatite and antibiotic coatings. At present there is no consensus on the prevention of pin site infection, and there is a paucity of randomized controlled trials on which to draw a conclusion. Whilst a number of these strategies have potential future use, many of the above strategies need further studies in animal models to ensure no cytotoxicity and prevention of osteointegration. Following this, well-designed randomized controlled clinical trials are required to give future ways to prevent external fixator pin site infections., (Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Background: The Oxford Unicompartmental Knee Replacement (OUKR) uses a mobile bearing to minimise wear. Bearing dislocation is a problem in the lateral compartment as the ligaments are loose in flexion. A domed tibial component has been introduced to minimise the risk of dislocation, yet they still occur, particularly medially. The aim of this mechanical study was to compare the domed and flat tibial components and to identify surgical factors that influence the risk of dislocation., Method: A jig was constructed to assess the amount of vertical distraction of the lateral OUKR for a dislocation to occur. Three methods of dislocation were assessed: laterally, medially, 'over the wall' and anteriorly. The study focused on medial dislocation., Results: Significantly (p=0.02) greater vertical distraction was required to dislocate the bearing with the domed tibia rather than the flat. For medial dislocation bearing distance from the wall, femoral component external rotation and tibial rotation were associated with significantly less distraction for dislocation. With the optimal technique with the domed tibia the distraction required to dislocate the bearing medially was 6.4 mm, whereas with poor technique it was 4.6 mm., Conclusions: This study suggests that to minimise the risk of dislocation the domed tibia should be used. The component should be implanted so the bearing is close to the wall, but does not hit it, and in flexion the femoral and tibial components should be neutrally aligned., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Obesity is considered to be a contraindication for unicompartmental knee replacement (UKR). The aim was to study the impact of BMI on failure rate and clinical outcome of the Oxford mobile bearing UKR., Method: Two thousand four hundred and thirty-eight medial Oxford UKRs were studied prospectively and divided into groups: BMI<25 (n=378), BMI 25 to <30 (n=856), BMI 30 to <35 (n=712), BMI 35 to <40 (n=286), and BMI 40 to <45 (n=126) and BMI≥45 (n=80)., Results: There was no significant difference in survival rate between groups. At a mean follow-up of 5years (range 1-12years) there was no significant difference in the Objective American Knee Society Score between groups. There was a significant (p<0.01) trend with the Oxford Knee Score (OKS) and Functional American Knee Society Scores decreasing with increasing BMI. As there was an opposite trend (p<0.01) in pre-operative OKS, the change in OKS increased with increasing BMI (p=0.048). The mean age at surgery was significantly (p<0.01) lower in patients with higher BMI., Conclusions: Increasing BMI was not associated with an increasing failure rate. It was also not associated with a decreasing benefit from the operation. Therefore, a high BMI should not be considered a contra-indication to mobile bearing UKR., Level of Evidence: IV., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Introduction: Patients undergoing knee arthroplasty are at high risk of developing post-operative deep vein thrombosis (DVT) or a pulmonary embolus (PE). Despite best efforts, the best prophylaxis for thromboembolic disease remains controversial. This article aims to update the reader on the newest guidelines concerning venous thromboembolism (VTE) prophylaxis for elective knee arthroplasty, highlighting their inconsistencies and why variations in recommendations exist., Methods: The Medline database and the Internet were searched for VTE prophylaxis guidelines in English. 12 guidelines were found and compared. The comparison looked at the recommendations made, the grade of recommendation, the level of evidence available for these recommendations and any inconsistencies between the guidelines., Results: Nearly all the guidelines advocate the use of low molecular weight heparin (LMWH) and Fondaparinux. There is little consensus in terms of other recommended drugs, the doses, duration and their recommendation grades. There are marked differences in the methodologies adopted by the different guideline working-groups., Conclusion: There is still uncertainty about the optimal methods of thromboprophylaxis in elective knee arthroplasty. Although there are always going to be disagreements about the endpoints amongst guideline makers, guidelines should achieve uniformity in their reporting of end-points, criteria for levels of evidence and recommendation grades, facilitating the clinician's decision-making process., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Introduction: Radiolucent lines (RLL) are commonly seen at the cement-bone interface of knee replacements, yet are poorly understood. Although thin RLL are not associated with implant loosening or poor patient outcome there is still concern that they indicate sub-optimal fixation. The primary study aim is to characterise the histology at the cement-tibia interface in Oxford unicompartmental knee replacement (UKR). The second aim is to assess whether a correlation exists between the presence of a RLL and the type of tissue that predominates at the interface., Methods: The radiology and histology of retrieved specimens of the interface from around firmly fixed tibial trays in ten patients undergoing revision between 1 and 19 years after Oxford UKR were studied., Results: Pre-revision radiographs showed the presence of both full and partial RLL. On contact radiographs of 5mm thick sections of the interface the total percentage of radiolucency ranged from 0 to 90% between patients. There was no consistent pattern for the distribution of radiolucency. Histological assessment demonstrated that under every tibial component there were areas where there was direct contact and interdigitation between bone and cement. The amount of direct bone-cement contact was between 19% and 95% of the tibial tray surface area. The remaining tissue was mainly fibrocartilage but there was also fibrous tissue. The presence of radiolucency was strongly inversely correlated with the percentage of cement-bone contact., Conclusion: This study demonstrates that even with partial or complete RLL seen on radiographs there is still cement-bone contact, thus indicating that there is stable fixation., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Single femoral radius TKRs have been reported to improve quadriceps' mechanical advantage, leading to enhanced patient function. An increased patellar tendon moment arm (PTMA) has been cited as the main feature leading to improved quadriceps' mechanical advantage. However, these designs often incorporate a recessed trochlea which alters the patellar mechanism and may contribute to improved quadriceps' mechanical advantage. This study simultaneously measured the PTMA using two and three dimensional methods, as well as quadriceps forces (QF), patellofemoral kinematics and tibiofemoral kinematics in a motion analysis laboratory during an open chain leg extension activity. Six cadaveric knees were tested in the normal state and after implantation of three different single femoral radius TKR designs: cruciate retaining, posterior stabilised and rotating platform posterior stabilised (Stryker, Newbury, UK). QFs in the TKRs were between 15% and 20% lower than normal between 60° and 70° flexion. The increase in PTMA was insufficient to explain the reduced QF in the TKRs. The patellar flexion angle (PFA) of the TKRs was lower than normal at knee flexion angles greater than 50°, probably as a result of the recessed trochlea. A simple patellar model demonstrated that the reduced PFA may explain a large proportion of the reduction in QF after single radius TKR., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Unicompartmental knee replacement (UKR) is a commonly performed procedure, suitable for one in four patients requiring knee replacement for end-stage osteoarthritis. Recovery and return of function is quicker than with total knee replacement (TKR), but little information is known about the recovery of muscle power. We prospectively studied a cohort of forty four patients undergoing medial UKR to document their functional recovery and leg extensor power. Muscle power was measured using a Leg Extensor Power rig preoperatively and at 1 and 2 years after surgery. Function was self reported using the Oxford Knee Score (OKS) and Tegner Activity Scale (TAS). At 1 year all patients had made significant improvements on all functional measures, with a mean gain in OKS of 15.9 and TAS of 0.84. There were also significant increases in leg extensor power (LEP) of both legs. The mean change in LEP of the operated leg at 1 year was 0.50 W/kg and the non-operated leg was 0.10 W/kg. Between 1 and 2 years there were very slight improvements in strength in both legs, but these were not significant. Compared with healthy age matched normative values, the UKR LEP values at 2 years after surgery were decreased. The recovery of strength and function following UKR had stabilised by 1 year and during the following year further improvements were minimal., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Intra-operative local anaesthetic infiltration provides good early pain relief after Unicompartmental Knee Replacement (UKR). However, appreciable pain may occur on the day after surgery. The purpose of this double-blinded, prospective randomised controlled trial was to evaluate the effectiveness of a bolus of local intra-articular anaesthetic given early on the day after surgery. Forty-four patients were randomised to receive an intra-articular injection, via an epidural catheter inserted at operation, of either 20 ml 0.5% plain bupivacaine or 20 ml normal saline. All patients received a femoral nerve block with 20 ml prilocaine 1% and local anaesthetic infiltration by the surgeon. Patients injected with bupivacaine had significantly less (p<0.001) pain than control patients immediately (mean pain score 1.82 v 6.1) and 6 hours (2.5 v 5.7) after injection. Patient satisfaction was also significantly greater (p<0.001) in the local anaesthetic group. We conclude that a bolus dose of intra-articular bupivacaine early on the day after surgery dramatically improves pain control after UKR and improves patient satisfaction., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Abnormal in vivo Total Knee Replacement (TKR) kinetics is influenced by a range of factors, particularly by changes to the knee's geometric parameters such as the patellar tendon moment arm (PTMA). In this study, ground reaction force (GRF) measurements were combined with simultaneous fluoroscopic image measurements to investigate the relationship between abnormal TKR kinetics and geometric parameters. Nine Scorpio Cruciate Retaining (CR) TKR (Stryker, Newbury, UK), nine Scorpio Posterior Stabilized (PS) TKR and seven normal subjects performed a step-up activity on a forceplate in view of a fluoroscope. The TKR subjects were part of a larger ongoing randomised controlled trial. The maximum external knee flexion moment was 22.0% lower in the Scorpio PS group compared to the Scorpio CR group. No significant differences in PTMA were found between the groups. The Scorpio PS had a low-riding patella, with a 30.7% reduction in patellar height compared to the Scorpio CR. This was probably due to using a thick tibial insert after PCL release in the PS, and led to an 8° increase in patellar flexion angle which altered the patellar mechanism and reduced quadriceps' mechanical advantage. Consequently, PS subjects stepped-up more cautiously with a reduced knee flexion moment., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Peri-prosthetic fractures (PPF) are a recognised complication following hip arthroplasty. Prosthesis design and type influence PPF pattern. Surgeons rely on classification systems, such as the Vancouver, to aid treatment planning. This study highlights a specific fracture pattern that occurs with cemented well-fixed polished, tapered, collarless (PTC) stems. We reviewed a consecutive series of 21 PPF around well fixed PTC stems. The majority of the fractures were classified pre-operatively as Vancouver B2 (14/21), but there were also B1 (6/21) and A type fractures. The B2 fractures had common radiological and intra-operative findings: a spiral fracture with extensive fragmentation of bone and cement, debonding of cement from the implant, cement fracture, and a well-fixed cement-bone interface. Reconstruction of these fractures was more difficult than suggested by the radiographs. Two of the six patients who were considered to have a Vancouver B1 fracture underwent open reduction and internal fixation (ORIF), and had treatment-related complications. Retrospective review of the radiographs showed subtle features, such as subsidence of the stem into the centraliser, that are characteristic of a B2 fracture pattern. In summary, it is important to recognise this fracture pattern around secure PTC stems in order to prevent misinterpretation of the fracture as a Vancouver B1 rather than a B2, leading to failure of treatment, and to alert the surgeon that complex reconstruction will be required because of the extensive fragmentation., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)

It is recommended that in medial compartment osteoarthritis (OA) unicompartmental knee replacement (UKR) should not be undertaken unless there is bone on bone. This recommendation is not evidence based and it is important to know if it is correct as there are many patients with pain and partial thickness cartilage loss (PTCL) who could potentially benefit from UKR. The aim of this study was to determine if the recommendation is valid. From our database of over 1000 patients treated with the Oxford UKR, we identified 29 with medial OA that had PTCL, confirmed at operation, but otherwise satisfied the recommended indications. This group was matched with 29 knees that had bone exposed (BE) on both sides of the medial compartment and 29 knees that had bone loss (BL) on both sides of the medial compartment. There was no significant difference in the demographics or preoperative scores between the three groups. At a mean follow up of 2 years (range 1-6) the Oxford Knee Score (OKS) of the PTCL group (mean 36 SD 10) was significantly (p < 0.001) worse than the OKS of either the bone exposed group (mean 43 SD 4) or the bone loss group (mean 43 SD 5). 21% of those with PTCL did not benefit substantially from the operation (increase in OKS ≤ 6), whereas all patients in the other groups did. We conclude that the results of UKR for PTCL are unpredictable and therefore that UKR should only be done for medial compartment OA if there is bone on bone. There is a need to develop a method to identify which patients with PTCL will do well so that this subgroup could be treated with UKR., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Hoffa's fat pad (HFP) of the knee is affected by a variety of tumours and tumour-like conditions. HFP can be affected by diffuse or solitary, focal disease. This paper reports a consecutive series of 19 cases of solitary symptomatic HFP tumours. The commonest presenting symptom was anterior knee pain. All patients underwent open excision after diagnostic magnetic resonance imaging (MRI). Histology revealed varied diagnoses with the commonest being pigmented villonodular synovitis (PVNS) and ganglia. American Knee Society scores improved from 76 pre-operatively to 96 post-operatively with an improvement in functional scores from 92 to 100. In conclusion the majority of solitary HFP tumours are benign and may be either cystic or solid. MRI and plain radiographs are the imaging of choice. The definitive treatments of both cystic and solid tumours should be selective arthrotomy and excision biopsy. All patients in this series reported substantial improvement in symptoms following surgery., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Accurate preoperative assessment of the patellofemoral joint is especially important in compartment specific knee arthritis. This study aims to show the actual intraoperative grade of patellofemoral cartilage damage that may be reliably detected or excluded by preoperative standard radiographic views. 100 consecutive knees awaiting arthroplasty underwent preoperative lateral and skyline radiographs and were scored using the Ahlback score. Intraoperative cartilage damage was assessed using the Collins score. The sensitivity and specificity were calculated for each grade of cartilage damage. Preoperative anterior knee pain and function were assessed and correlated to the degree of cartilage damage. The lateral radiograph shows poor sensitivity for all grades of disease (0.05-0.23). The skyline shows good sensitivity for grade 4 (large full thickness) damage (0.90) but decreases substantially for grades 1-3 (0.19-0.46). Significantly more people with skyline radiograph joint space narrowing complained of anterior knee pain than those with a normal radiograph (p<0.001). There was only a poor correlation between preoperative anterior pain and intraoperative patellofemoral cartilage damage (r=0.24). The lateral radiograph cannot exclude even large areas of full thickness cartilage damage whereas a normal skyline radiograph can reliably exclude significant (grade 4) patellofemoral disease and should be used in addition to the lateral view., (Copyright © 2009 Elsevier B.V. All rights reserved.)

Despite the theoretical advantages of mobile bearings for lateral unicompartmental replacement (UKR), the failure rate in the initial published series of lateral Oxford UKR's was unacceptably high. The main cause of failure was bearing dislocation. To address this problem we first modified the surgical technique and then introduced a new design with a convex domed tibial plateau. This paper presents the results of these changes. In the original series (n=53), implanted using a standard open approach, there were six dislocations, all of which occurred in the first year. Five of the dislocations were primary and one was secondary to trauma. In the second series (n=65), with the modified technique, there were three dislocations, all of which were primary and occurred in the second and third year. In the third series (n=101, 69 with a minimum 1-year follow-up), with the modified technique and the domed tibial plateau, there was one dislocation which was secondary to trauma and occurred in the second year. At 4 years the dislocation rates in the three series were 11%, 5% and 1.7% and the primary dislocation rates were 10%, 5% and 0%. Both the overall and the primary dislocation rates were significantly different (p=0.04 and p=0.03) in the different series. The combination of the modified surgical technique and new design with a domed tibial component appears to have reduced the early dislocation rate to an acceptable level., (Copyright © 2009 Elsevier B.V. All rights reserved.)

Revision is the gold standard outcome measurement for survival analyses of orthopaedic implants but reliance on revision as an endpoint has been recently questioned. This study, that assesses long-term outcome in a specific group of patients who had undergone total knee replacement (TKR) for osteoarthritis, highlights the main problems facing modern survival analyses. Minimum 12-year survival and outcome data were reviewed for a series of sixty patients under the age of 60 years (mean age 55.4 years) who underwent total knee replacement (TKR) for osteoarthritis. The patients are a subgroup from a larger consecutive series of 1429 patients who underwent TKR between 1987 and 1993 at a single institution. Whilst the main study aim was to compare outcome of TKR using different endpoints, the outcome of TKR in this younger subpopulation could also be investigated. With revision as the primary endpoint the survival for TKR was 82.2% (95% CI 17.3). The mean OKS at follow-up (mean 15.7 years) was 30.9. However, many of the 82% of patients who did not undergo revision had a less than satisfactory outcome. 41% of these patients reported modest or severe pain (using the OKS) at final follow-up. A combined endpoint including revision, poor function and significant pain drastically reduced the survival rate for the operation. Survival based on revision alone provides an acceptable but inaccurate impression of outcome in younger TKR patients (under 60 years). A true representation of the success of TKR should include pain and function as endpoints.

As implants are made in incremental sizes and usually do not fit perfectly, surgeons have to decide if it is preferable to over or undersize the components. This is particularly important for unicompartmental knee replacement (UKR) tibial components, as overhang may cause irritation of soft tissues and pain, whereas underhang may cause loosening. One hundred and sixty Oxford UKRs were categorised according to whether they had minor (<3 mm, 70%) or major (>or=3 mm, 9%) tibial overhang, or tibial underhang (21%). One year post surgery, there was no significant difference in outcome between the groups. Five years after surgery, those with major overhang had significantly worse Oxford Knee Scores (OKS) (p=0.001) and pain scores (p=0.001) than the others. The difference in scores was substantial (OKS=10 points). There was no difference between the 'minor overhang' and the 'underhang' group. We conclude that surgeons must avoid tibial component overhang of 3 mm or more, as this severely compromises the outcome. Although this study showed no difference between minor overhang or underhang, we would advise against significant underhang because of the theoretical risk of component subsidence and loosening.

It is difficult to determine the ideal size of femoral component when a unicompartmental knee replacement (UKR) is implanted with a minimally invasive approach. The aim of the study was to identify the best method of determining femoral component size pre-operatively. This was done by assessing the accuracy with which it could be predicted by pre-operative templating, patient height, gender and tibial component size. One hundred patients who had had Oxford UKR were studied. Pre-operative radiographs were templated and patient height, gender and implanted tibial component size were recorded. From a review of post-operative radiographs and the known size of component used the ideal size of component that should have been used was established. By relating patient height, gender and tibial component size to the ideal femoral component size the range of these various parameters that best predicted each component size was identified. The reliability of these predictions was assessed assuming that a component one size off ideal was acceptable and two sizes off was unacceptable. Templating was correct in 67% of cases, acceptable in 33% and was never unacceptable. Height alone was correct in 56%, acceptable in 38% and unacceptable in 6%. Height based on gender was correct in 75%, acceptable in 25% and was never unacceptable. Tibial size was correct in 56%, acceptable in 41% and unacceptable in 3%. We conclude that both templating and height based on gender are reliable methods of assessing femoral component size. However because errors can occur surgeons are advised to use both.

The in vivo kinematics of 10 patients after combined anterior cruciate ligament reconstruction (ACLR group) and Oxford unicompartmental knee arthroplasty (UKA) was compared to those of 10 Oxford UKA patients with an intact ACL (ACLI group) and a group of 22 normal knees. The kinematics during a step-up exercise and a deep knee bend exercise was measured using a fluoroscopic technique. The patellar tendon angle (PTA) to knee flexion angle relationship during both exercises was similar for all three groups of subjects. For the UKA groups the pattern of mobile bearing movement during both exercises was similar. This study demonstrates that normal knee kinematics is achieved in the ACL deficient arthritic knee following ACLR and UKA. As a result these patients, who tend to be young and high demand, have excellent outcome and achieve high levels of function. As the relative position of the components and thus component loading are similar to the ACLI UKA, we would expect similar long term survival.